Membrane System to Treat Leachate and Methods of Treating Leachate

ABSTRACT

Embodiments of the present disclosure provide for systems for removing contaminants from a leachate, methods of removing contaminants from a leachate, and the like.

CLAIM OF PRIORITY TO RELATED APPLICATION

This application is a continuation of, and claims priority to,co-pending U.S. patent application Ser. No. 13/886,321, filed in theUnited States entitled “MEMBRANE SYSTEM TO TREAT LEACHATE AND METHODS OFTREATING LEACHATE” on May 3, 2013, which is entirely incorporated hereinby reference. U.S. patent application Ser. No. 13/886,321, claimspriority to co-pending U.S. provisional application entitled “MEMBRANESYSTEM TO TREAT LEACHATE AND METHODS OF TREATING LEACHATE” having Ser.No. 61/642,494, filed on May 4, 2012, which is entirely incorporatedherein by reference. U.S. patent application Ser. No. 13/886,321, claimspriority to co-pending U.S. provisional application entitled “MEMBRANESYSTEM TO TREAT LEACHATE AND METHODS OF TREATING LEACHATE” having Ser.No. 61/773,218, filed on Mar. 6, 2013, which is entirely incorporatedherein by reference. U.S. patent application Ser. No. 13/886,321, claimspriority to co-pending U.S. provisional application entitled “MEMBRANESYSTEM TO TREAT LEACHATE AND METHODS OF TREATING LEACHATE” having Ser.No. 61/777,138, filed on Mar. 12, 2013, which is entirely incorporatedherein by reference.

BACKGROUND

Researchers estimate that between 900 million to 9 billion gallons oflandfill leachate are produced annually in the United States, with anestimated 250 million gallons annually being managed in Florida. Thisvolume of wastewater raises environmental and economic concerns, andrepresents an opportunity to reclaim both water and nutrients from awastewater stream that is currently being “thrown away.”

Leachate is water is partly inherent in solid waste and partly theresult of rainfall that falls on the wastes after placement in alandfill, which subsequently becomes contaminated with a variety ofchemicals contained in the solid waste. Landfill leachate ischaracterized by heavy metals, high chemical oxygen demand (COD) andbiological oxygen demand (BOD) compounds, total organic carbon (TOC),volatile organic carbons (VOC), ammonia-nitrogen, suspended solids andcan contain other compounds that resist biological decomposition.Chemical constituents of leachate can be toxic or carcinogenic, andcertain compounds can emit objectionable odors. Landfill leachate canalso transport viruses and bacteria harmful to human health.

Leachate management methodologies became necessary in the 1980's whenthe US Environmental Protection Agency (EPA) and state regulatoryagencies began adopting the “dry tomb” approach to landfill constructionwhich requires new landfill cells to have bottom and top liners, as partof leachate management systems. Soon after implementing theseregulations researchers began to investigate the effects of adding wateror recirculating leachate to the lined cells. This research confirmedthat recirculation of leachate accelerates gas production and thedegradation of organic waste. This so called “wet cell” research led tothe development of “bioreactor landfills” in which significantquantities of leachate are recirculated while organic waste is beingdegraded. Once biological activity in the cells ceases, however,bioreactor landfill operators need methods to dewater the cells anddispose of or treat the leachate.

Leachate is managed in a variety of ways including trucking or pipingleachate to a wastewater treatment plant (WWTP), deep well injectionwith minimal treatment, evaporation, biological uptake of constituentsin engineered wetlands, and various chemical treatment processes. Somefacilities use more than one method. All methods of processing leachateuse energy and can have negative environmental impacts. Few WWTPs aredesigned to treat leachate, which disrupts biological treatment in allbut the smallest amounts.

An on-site treatment method that minimizes energy consumption andadverse impacts such as odors, captures the inherent macro and micronutrients in the leachate, segregates heavy metals and VOCs, dewatersthe cell, and provides reuse of the decontaminated water is thereforedesirable.

Thus there is a need to address and/or overcome these deficiencies.

SUMMARY

In accordance with the purpose(s) of the present disclosure, as embodiedand broadly described herein, embodiments of the present disclosure, inone aspect, relate to a systems for removing contaminants from aleachate, methods of removing contaminants from a leachate, and thelike.

In an embodiment, a membrane system, among others, includes: a firststage including one or more membranes selected from the group consistingof: a reverse osmosis membrane and a nanofiltration membrane, wherein aleachate is introduced to the first stage to separate the leachate intoa first stage concentrate and a first stage permeate; and a second stageincluding one or more membranes selected from the group consisting of: areverse osmosis membrane and a nanofiltration membrane, wherein thefirst stage and the second stage are in fluidic communication, whereinthe first stage permeate is introduced to the second stage to separatethe first stage permeate into a second stage concentrate and a secondstage permeate. In an embodiment, the first stage and the second stageis adapted to reject about 95% or more of contaminates in the leachate.

In an embodiment, a method of treating leachate, among others, includes:introducing a leachate to a first membrane system to separate theleachate into a first stage concentrate and a first stage permeate, andintroducing the first stage permeate to a second membrane system toseparate the first stage permeate into a second stage concentrate and asecond stage permeate. In an embodiment, the second stage permeate hasabout 95% less contaminates than the leachate.

In an embodiment, a recursive concentrate reduction membrane system,among others, includes: a first stage including one or more membranesselected from the group consisting of: a reverse osmosis membrane and ananofiltration membrane, wherein a leachate is introduced to the firststage to separate the leachate into a concentrate and a permeate. In anembodiment, the first stage and the second stage is adapted to rejectabout 95% or more of contaminates in the leachate.

In an embodiment, a method of treating leachate, among others, includes:introducing a leachate to a membrane system to separate the leachateinto a concentrate and a permeate, wherein the permeate has about 5% orless of contaminates of the leachate.

In an embodiment, a method of treating leachate, among others, includes:introducing a leachate to a membrane system to separate the leachateinto a concentrate and a permeate, wherein the concentrate and permeateare mixed or used separately to produce a fertilizer for terrestrial oraquatic substrates. In an embodiment the leachate is treated usingvarious applied pressures which produce a target water quality ofconcentrate and permeate that is mixed or used separately to produce afertilizer, fertilizer-equivalent, or partial-fertilizer for terrestrialand aquatic substrates.

Other structures, compositions, methods, features, and advantages willbe, or become, apparent to one with skill in the art upon examination ofthe following drawings and detailed description. It is intended that allsuch additional structures, systems, methods, features, and advantagesbe included within this description, be within the scope of the presentdisclosure, and be protected by the accompanying claims.

BRIEF DESCRIPTION OF THE DRAWINGS

Many aspects of this disclosure can be better understood with referenceto the following drawings. The components in the drawings are notnecessarily to scale, emphasis instead being placed upon clearlyillustrating the principles of the present disclosure. Moreover, in thedrawings, like reference numerals designate corresponding partsthroughout the several views.

FIG. 1 includes a membrane system that can be used to treat leachate toremove contaminants.

FIG. 2 shows a schematic of a membrane system that treats landfillleachate.

FIG. 3 shows a schematic of an alternative configuration for a membranesystem that treats landfill leachate.

FIG. 4 shows a schematic of an alternative configuration that mayrealize additional dewatering and energy efficiencies.

FIG. 5 shows a schematic of an alternative configuration that mayrealize additional dewatering and energy efficiencies.

FIG. 6 is a diagram of the recursive concentrate reduction system.

FIG. 7 is a diagram of the recursive concentrate reduction systemdrawing from a leachate collection tank rather than directly from thesump.

DETAILED DESCRIPTION

Before the present disclosure is described in greater detail, it is tobe understood that this disclosure is not limited to particularembodiments described, as such may, of course, vary. It is also to beunderstood that the terminology used herein is for the purpose ofdescribing particular embodiments only, and is not intended to belimiting, since the scope of the present disclosure will be limited onlyby the appended claims.

Where a range of values is provided, it is understood that eachintervening value, to the tenth of the unit of the lower limit (unlessthe context clearly dictates otherwise), between the upper and lowerlimit of that range, and any other stated or intervening value in thatstated range, is encompassed within the disclosure. The upper and lowerlimits of these smaller ranges may independently be included in thesmaller ranges and are also encompassed within the disclosure, subjectto any specifically excluded limit in the stated range. Where the statedrange includes one or both of the limits, ranges excluding either orboth of those included limits are also included in the disclosure.

Unless defined otherwise, all technical and scientific terms used hereinhave the same meaning as commonly understood by one of ordinary skill inthe art to which this disclosure belongs. Although any methods andmaterials similar or equivalent to those described herein can also beused in the practice or testing of the present disclosure, the preferredmethods and materials are now described.

All publications and patents cited in this specification are hereinincorporated by reference as if each individual publication or patentwere specifically and individually indicated to be incorporated byreference and are incorporated herein by reference to disclose anddescribe the methods and/or materials in connection with which thepublications are cited. The citation of any publication is for itsdisclosure prior to the filing date and should not be construed as anadmission that the present disclosure is not entitled to antedate suchpublication by virtue of prior disclosure. Further, the dates ofpublication provided could be different from the actual publicationdates that may need to be independently confirmed.

As will be apparent to those of skill in the art upon reading thisdisclosure, each of the individual embodiments described and illustratedherein has discrete components and features which may be readilyseparated from or combined with the features of any of the other severalembodiments without departing from the scope or spirit of the presentdisclosure. Any recited method can be carried out in the order of eventsrecited or in any other order that is logically possible.

Embodiments of the present disclosure will employ, unless otherwiseindicated, techniques of chemistry, physics, and the like, which arewithin the skill of the art. Such techniques are explained fully in theliterature.

The following examples are put forth so as to provide those of ordinaryskill in the art with a complete disclosure and description of how toperform the methods and use the compositions and compounds disclosed andclaimed herein. Efforts have been made to ensure accuracy with respectto numbers (e.g., amounts, temperature, etc.), but some errors anddeviations should be accounted for. Unless indicated otherwise, partsare parts by weight, temperature is in ° C., and pressure is at or nearatmospheric. Standard temperature and pressure are defined as 20° C. and1 atmosphere.

Before the embodiments of the present disclosure are described indetail, it is to be understood that, unless otherwise indicated, thepresent disclosure is not limited to particular materials, reagents,reaction materials, manufacturing processes, or the like, as such canvary. It is also to be understood that the terminology used herein isfor purposes of describing particular embodiments only, and is notintended to be limiting. It is also possible in the present disclosurethat steps can be executed in different sequence where this is logicallypossible.

It must be noted that, as used in the specification and the appendedclaims, the singular forms “a,” “an,” and “the” include plural referentsunless the context clearly dictates otherwise. Thus, for example,reference to “a support” includes a plurality of supports. In thisspecification and in the claims that follow, reference will be made to anumber of terms that shall be defined to have the following meaningsunless a contrary intention is apparent.

General Discussion

Embodiments of the present disclosure provide for systems for removingcontaminants from a leachate, methods of removing contaminants from aleachate, and the like. In particular, embodiments of the presentdisclosure provide for membrane systems and methods of using membranefiltration and diffusion such as reverse osmosis and/or nanofiltrationto remove contaminates from a leachate. Embodiments of the presentdisclosure can be advantageous in that contaminates can be substantiallyremoved from a leachate such as one from a landfill in an economicalmanner.

In an embodiment, the contaminants can include heavy metals, highchemical oxygen demand (COD) and biological oxygen demand (BOD)compounds, total organic compounds (TOC), volatile organic compounds(VOC), ammonia-nitrogen, suspended solids and can contain othercompounds that resist biological decomposition.

In an exemplary embodiment, a membrane system that can be used to treatleachate, such as landfill leachate, to remove contaminants by use of asingle stage, a two stage, or a multi-stage (e.g., 3, 4, 5, and thelike) system is provided and described in the figures.

An exemplary embodiment of the present disclosure as shown in FIGS. 6and 7 includes a membrane system that can be used to treat leachate toremove contaminants using a single stage system or a recursiveconcentrate reduction system. While the recursive concentrate reductionsystem may be considered to have two stages, the product of the “1^(st)stage” is clean water. The 2^(nd) stage treats the waste from the 1^(st)stage so that a significant portion of it can be recycled through theprocess back to the 1^(st) stage. FIG. 7 is a diagram of the recursiveconcentrate reduction system drawing from a leachate collection tankrather than directly from the sump, as shown in FIG. 6. Although FIGS. 6and 7 provide specific dimensions of the membranes and the achievementof certain reductions in contaminants, these are only for illustrativepurposes, and embodiments of the present disclosure are not limited bythese.

In an embodiment for a recursive concentrate reduction system, the firststage of the recursive concentrate reduction membrane system can includeone or more reverse osmosis (RO) membranes and/or nanofiltrationmembranes that are connected in series, parallel, or a combinationthereof. Raw leachate or pre-filtered leachate can be pumped through themembrane(s) to form a concentrate and a permeate. Based on the number ofstages the recovery rate of permeate (volume of water recovered to feedwater treated) can vary from about 20% to 90%. In an embodiment,components of the first stage can be connected using pipes. In anembodiment, one or more pipes can be used to flow, independently, thepermeate and the concentrate out of the membranes to appropriatedestinations.

In an embodiment, the concentrate can be additionally filtered andrecycled back to the first stage (See FIGS. 6 and 7), re-circulated tothe landfill, moved to a treatment plant, and/or injected into a deepwell. In an embodiment, the permeate can be used in irrigation and/or aswater for livestock. In an embodiment, the permeate can achieve about90% or more, about 95% or more, about 98% or more, or about 99% or more,rejection of most contaminants that were in the raw leachate. Thepermeate has about 1% or less of the chloride, ammonia, total dissolvedsolids, and most toxic metals found in the raw leachate. In certainembodiments, a dewatering yield of about 20% to 95% can be achieved.

An exemplary embodiment of the present disclosure as shown in FIG. 1includes a membrane system that can be used to treat leachate, such aslandfill leachate, to remove contaminants using a first stage and asecond stage that are in fluidic communication.

In an embodiment, the first stage of the membrane system can include aone or more reverse osmosis (RO) membranes and/or nanofiltrationmembranes that are connected in series, parallel, or a combinationthereof. Raw leachate or pre-filtered leachate can be pumped through themembrane(s) to form a first stage concentrate and a first stagepermeate. The permeate recovery rate of this first stage is expected tovary from about 15% and 90% depending on the number and arrangement ofthe membranes. In an embodiment, components of the first stage can beconnected using pipes. In an embodiment, one or more pipes can be usedto flow the permeate out of the membranes to the second stage and one ormore pipes can be used to flow the first stage concentrate to the othermembrane(s) and/or to other destinations. In an embodiment, the firststage concentrate can be recirculated to the landfill, moved to atreatment plant, and/or injected into a deep well. In an embodiment, thefirst stage permeate can be flowed to the second stage of the membranesystem, used as a flora fertilizer, and/or returned to the leachatesump/wet well to mix with the raw leachate. In an embodiment where thefirst stage permeate is returned to the sump/wet well, the salinity ofthe raw leachate is reduced which reduces the osmotic pressure requiredto pump the leachate through the membrane system. In an embodiment, thefirst stage permeate can achieve about 90% or more, or about 95% ormore, rejection of most or all of the contaminants that were in the rawleachate. The first stage permeate has about 10% or less of thechloride, ammonia, total dissolved solids, and most toxic metals foundin the raw leachate.

In an embodiment, the second stage of the membrane system can includeone or more RO membranes and/or nanofiltration membranes that areconnected in series, parallel, or a combination thereof. After flowingthrough the second stage, the first stage permeate is separated into asecond stage concentrate and a second stage permeate. The permeaterecovery rate of this stage is expected to vary from about 15% and 40%depending on the arrangement of membranes. In an embodiment, one or morepipes can be used to flow the permeate out of the membranes to thedesired location and one or more pipes can be used to flow theconcentrate to the other membrane(s) and/or to other destinations. In anembodiment, the second stage concentrate can be used as a florafertilizer, in landfill recirculation, and/or returned to the leachatesump/wet well to mix with the raw leachate. In an embodiment where thesecond stage concentrate is returned to the sump/wet well, the salinityof the raw leachate is reduced which reduces the osmotic pressurerequired to pump the leachate through the membrane system. In anembodiment, the second stage permeate can be used in irrigation and/oras water for livestock. In an embodiment, the second stage permeate canachieve about 90% or more, about 95% or more, about 98% or more, orabout 99% or more, rejection of most contaminants that were in the rawleachate. The second stage permeate has about 1% or less of thechloride, ammonia, total dissolved solids, and most toxic metals foundin the raw leachate. In certain embodiments, a dewatering yield of about20% to 95% can be achieved.

In an embodiment, the RO and nanofiltration membranes can includespiral, tubular, hollow fiber, cellulose acetate, composite polyamide,or a combination thereof. In an embodiment, the dimensions of themembranes can be about 4 inches to 8 inches in diameter and 40 inches to60 inches in length. In an embodiment, in the design of the membranesystem and in the selection of the RO and/or nanofiltration membranes ineach stage, one should consider the relative surface area of themembranes in each stage and the pressure as well as whether the ROmembranes are in series, parallel, or a combination, so that both firstand second stage permeate flows are equal.

In an embodiment, the RO and/or nanofiltration membranes can be cleanedby conventional membrane cleaning procedures such as by manual operatoror automatic actuators that change various valve positions.

In an embodiment, the RO and/or nanofiltration membranes can includethose that were previously used at potable treatment plants, so anadditional advantage is realized by recycling the RO and/ornanofiltration membranes. In addition, the RO and/or nanofiltrationmembranes can be cleaned and reused to further reduce costs.

In an embodiment, the membrane system can include one or more pumps tocause the leachate, concentrate, and permeate to flow through themembrane system, in particular the RO and/or nanofiltration membranes.The pressure that can be used can depend upon the design of the membranesystem, the RO membranes, the nanofiltration membranes, the leachate,the concentrate, the permeate, the desired flow rate, the desireddewatering rate, and the like. In general the pressure can be about 50to 800 psi. In certain embodiments, the membrane system uses lowerpressures to reduce energy consumption, i.e., the first stage operatingat about 50 to 300 psi and the second stage is operating at about 50 to300 psi.

In an embodiment, the membrane system can include one or more filters toremove larger particles from the leachate, the concentrate, and/or thepermeate. This may be done to improve the efficiencies of the membranesystem and RO and/or nanofiltration membranes and increase their usefullifetime.

In an embodiment, nanofiltration membranes can be used in conjunctionwith RO membranes to further treat the leachate. In this configuration,a higher permeate recovery and dewatering rate is achieved.

In an embodiment, the membrane system can include other components suchas storage tanks, flow controllers, computer system to monitor the flow,sensors to monitor the level of contaminants and other components in theleachate, the concentrate, and/or the permeate, and the like.

In an embodiment, the leachate, the concentrate, and/or the permeate,can be subject to chemical treatment to increase the removal of one ormore contaminants. For example, the leachate, the concentrate, and/orthe permeate, can be subjected to pH change to increase the removal ofcertain metals via precipitation.

It can be advantageous that the permeate (e.g., “single pass” systempermeate or second stage permeate) meets U.S. environmental dischargestandards. In an embodiment, this can be obtained using a recursiveconcentrate reduction system. In an embodiment, this can be obtained bythe use of the second stage of the membrane system, which removesadditional contaminants from the first stage permeate.

Another advantage includes capturing beneficial nutrients in first stagepermeate and second stage concentrate and re-using these constituents,including ammonia-nitrogen, as a fertilizer for cultivating variousphotosynthetic flora has been demonstrated. In an embodiment, the firststage permeate and second stage concentrate is equivalent to commercialliquid fertilizer.

Another advantage is derived by mixing of second stage concentrateand/or the first stage permeate with raw leachate in the leachate sump,which enhances system operational stability by decreasing the initialfeed stock salinity during operation.

In an embodiment, the process can include flowing the raw leachate froma landfill cell to a collection sump. The raw leachate can be pumpedthrough a filter (e.g., a one micron filter), and the filtered leachateis further pressurized before entering the first stage of membranesystem to produce, which produces two product flows, a first stagepermeate and a first stage concentrate. The first concentrate can bere-circulated back into the landfill cell, while the first stagepermeate can be pumped through a second one-micron filter, and thenfurther pressurized before entering the second stage of membrane system,which also produces two products, the second stage concentrate and thesecond stage permeate.

In an embodiment, the second stage concentrate has been effectivelystripped of all landfill contaminants except for ammonia-nitrogen atroughly about 100 ppm and some macro-nutrients and micro-nutrients. Inan embodiment, the second stage concentrate is suitable as a liquidfertilizer that can used to grow a number of plant species.

In an embodiment, the second stage permeate has been stripped of mostall (e.g., about 95 or more or about 99% or more) landfill contaminantsexcept for ammonia-nitrogen at about 5 ppm, just above the US EPAgroundwater standard of 2.8 ppm. At that level of purity, it can besafely discharged to a landfill spray field where vegetative cover, suchas turf grass, uptake the remaining ammonia. In an embodiment, the firststage permeate has been stripped of most all (e.g., about 90 or more orabout 95% or more) landfill contaminants except for ammonia-nitrogen atabout 100 ppm. The first stage permeate is safely discharged to alandfill spray field where vegetative cover, such as turf grass, uptakethe remaining ammonia and/or the first stage permeate is used as florafertilizer.

In an embodiment, the flow ratio of second stage permeate to rawleachate achieved can be about 20%. If all of the second stageconcentrate is used as a liquid fertilizer by algae or various plantspecies, the de-watering yield would be about 50%.

FIG. 2 shows a schematic of a membrane system that treats landfillleachate. The membrane system includes a first stage (top portion) and asecond stage (bottom portion). The first stage of the membrane systemcan include a pair of reverse osmosis (RO) membranes that are connectedin series; however, more than two RO membranes could be used and/ornanofiltration membranes may be added or used. The number and dimensionsof the RO membranes in the first stage can vary depending upon the use(e.g., amount of water flowing, particles present, the design of thesecond stage, and the like). The first stage permeate can be directed tothe second stage. The second stage of the membrane system can includefour RO membranes that are connected in series; however, more than fourRO membranes could be used and/or nanofiltration may be added or used.The number and dimensions of the RO membranes in the second stage canvary depending upon the use (e.g., amount of water flowing, particlespresent, the design of the first stage, use of the second stagepermeate, and the like).

In general, the treatment process using the system shown in FIG. 2 isdescribed below. Step 1: Raw, untreated leachate is collected and storedin a sump. Leachate is then pumped at about 20 to 30 psig through a onemicron filter to remove suspended particulates from the leachate. Thepump, pressure of pumping and the filter can be modified to suit desiredneeds and results. Step 2: The filtered leachate is then pumped to ahigher pressure of about 240 psig or more to the first stage of the ROsystem. The first stage system can include two, 8-inch diameter by 10foot RO membranes, for example. Concentrate from the first vessel is fedin series to the second 8-inch RO membranes. Permeate from both vesselsare mixed and delivered to a storage tank. Permeate from this stage hasachieved in excess of 95% rejection of most contaminants, for example.This permeate may be considered final in an embodiment, or moretreatment (e.g., removal) may be performed. Step 3: Concentrate from theRO membrane is recirculated under pressure to the landfill, for example,or further treated to reduce its volume using other membranes. Step 4:The second stage of the RO system uses four, 4-inch diameter by 40-inchlength RO spiral wound membranes connected in series, for example. Thisstage can produce two effluents: second stage concentrate and secondstage permeate. The second stage concentrate is sent back to theleachate storage to mix with the raw leachate. The pressure energy mayalso be recovered to drive other stages of the process. In anembodiment, the system can include a pressure exchanger which can beused to transfer pressure energy from a high pressure concentrate streamto a low pressure concentrate stream. The second stage permeate is sentto an irrigation holding tank, for example. The second stage achieves inexcess of 95% rejection of most of the remaining contaminants. Step 5:The stored permeate is used to irrigate the landfill's vegetative cover,for example. The vegetative cover consumes the ammonia-nitrogenremaining in the permeate allowing for low nutrient discharge.

FIG. 3 shows a schematic of an alternative configuration for a membranesystem that treats landfill leachate. Steps 1 to 3 are the same as inFIG. 2. This configuration differs at step 4, where first stage permeateis treated via two potential methods, both of which remove remainingammonia-nitrogen. One demonstrated polishing methodology utilizesaquatic flora photo synthesis (step 4 a), while the other polishingmethodology uses the permeate in terrestrial farming applications (step4 b). This configuration of the system achieves a 50% dewatering yieldas well as producing a liquid fertilizer equivalent to commercialfertilizers.

FIGS. 4 and 5 show schematics of alternative configurations that mayrealize additional dewatering and energy efficiencies. FIG. 6 shows aschematic of an alternative configuration that treats the concentratefurther to achieve higher permeate recovery rates. FIG. 6 illustratesthe use of a surge tank, which can store the concentrate and permeategenerated from one of more stages. In an embodiment, the storedconcentrate and permeate can be held until a specified volume is reachedand the stock in the surge tank can be introduced to the leachate. Thusthe treated concentrate may be recycled to the beginning of the process,being cleaner than the feedwater. FIG. 7 shows the same process as FIG.6 drawing from an intermediate leachate storage vessel, rather than fromthe sump.

It should be noted that ratios, concentrations, amounts, and othernumerical data may be expressed herein in a range format. It is to beunderstood that such a range format is used for convenience and brevity,and thus, should be interpreted in a flexible manner to include not onlythe numerical values explicitly recited as the limits of the range, butalso to include all the individual numerical values or sub-rangesencompassed within that range as if each numerical value and sub-rangeis explicitly recited. To illustrate, a concentration range of “about0.1% to about 5%” should be interpreted to include not only theexplicitly recited concentration of about 0.1 wt % to about 5 wt %, butalso include individual concentrations (e.g., 1%, 2%, 3%, and 4%) andthe sub-ranges (e.g., 0.5%, 1.1%, 2.2%, 3.3%, and 4.4%) within theindicated range. In an embodiment, the term “about” can includetraditional rounding according to the measurement technique and the typeof numerical value. In addition, the phrase “about ‘x’ to ‘y’” includes“about ‘x’ to about ‘y’”.

It should be emphasized that the above-described embodiments of thepresent disclosure are merely possible examples of implementations, andare merely set forth for a clear understanding of the principles of thisdisclosure. Many variations and modifications may be made to theabove-described embodiment(s) of the disclosure without departingsubstantially from the spirit and principles of the disclosure. All suchmodifications and variations are intended to be included herein withinthe scope of this disclosure and protected by the following claims.

We claim at least the following:
 1. A method of treating leachate,comprising: introducing a leachate to a first membrane system toseparate the leachate into a first stage concentrate and a first stagepermeate, and introducing the first stage permeate to a second membranesystem to separate the first stage permeate into a second stageconcentrate and a second stage permeate.
 2. The method of claim 1,further comprising: introducing a raw leachate to a prefilter to form aleachate.
 3. The method of claim 1, further comprising: mixing the firststage concentrate with the leachate as the first stage concentrate isformed.
 4. The method of claim 1, further comprising: mixing the secondstage concentrate with the leachate as the second stage concentrate isformed.
 5. The method of claim 1, wherein the first membrane systemincludes two or more reverse osmosis and nanofiltration membranesconnected to one another in series, in parallel, or in a combination ofseries and parallel.
 6. The method of claim 1, wherein the secondmembrane system includes two or more reverse osmosis and nanofiltrationmembranes connected to one another in series, in parallel, or in acombination of series and parallel.
 7. A recursive concentrate reductionmembrane system, comprising: a first stage including one or moremembranes selected from the group consisting of: a reverse osmosismembrane and a nanofiltration membrane, wherein a leachate is introducedto the first stage to separate the leachate into a concentrate and apermeate and, a second stage including one or more membranes selectedfrom the group consisting of: a reverse osmosis membrane and ananofiltration membrane, wherein the first stage and the second stageare in fluidic communication, wherein the concentrate is introduced tothe second stage to separate the concentrate into a second stageconcentrate and a second stage permeate
 8. The membrane system of claim7, further comprising: a surge tank, wherein the surge tank stores thesecond stage and third stage, concentrate and permeate until a specifiedvolume is reached and the stock in the surge tank is introduced to theleachate.
 9. The membrane system of claim 7, further comprising: acollection tank, wherein the collection tank stores leachate from theleachate source and the second stage and third stage concentrate andpermeate, wherein the liquid inflow is adjusted to maintain a dilutionfactor within the tank stock that optimizes system performance.
 10. Amethod of treating leachate, comprising: introducing a leachate to amembrane system to separate the leachate into a concentrate and apermeate, wherein a second stage permeate has about 1% of thecontaminants of the leachate.
 11. The method of claim 10, furthercomprising: introducing a raw leachate to a prefilter to form aleachate.
 12. The method of claim 10, further comprising: mixing theconcentrate with the leachate as the concentrate is formed.
 13. Themethod of claim 10, wherein the membrane system includes two or moremembranes connected to one another in series, in parallel, or in acombination of series and parallel.
 14. A method of treating leachate,comprising: introducing a leachate to a membrane system to separate theleachate into a concentrate and a permeate, wherein the concentrate andpermeate are mixed or used separately to produce a fertilizer forterrestrial or aquatic substrates.
 15. The method of claim 14, whereinthe leachate is treated using various applied pressures, wherein theapplied pressures produce a target water quality of concentrate andpermeate that is mixed or used separately to produce a fertilizer,fertilizer-equivalent, or partial-fertilizer for terrestrial and aquaticsubstrates.